Steam generator



Oct. 26, 1943. G. H.. DANIELS STEAM GENERATOR Filed Sept. 7, 1938 N0)."; I Vi I WW. Georg Patented Oct. 26,1943 I I V I UNITED [STATESe-A'r STEAM GENERATOR George H. Daniels, Westfield,.N. J-., assignor toQ I The Babcock & Wilcox Company, N ewark, N. J., acorporation of NewJersey Application September 7, 1938Q'SerialNo. 228,747

' r -2 Claims. (or. 122-473 The present invention relates to theconstruction and operation of steam generating units, and moreparticularly, to water tube steam boilers particularly designed for andespecially -useful in marine installations.

Steam generating installations in the marine field are characterized byrelative lowspace, weight, headroom andother limitations, allcontributing towards an extremely compact'lightweight generator designwithout sacrifice: of efficiency requiring a minimum of specialconstruction of the surroundingship structure. The recent trend in thisfield towards units adapted to generate high pressure high temperature"steam with relatively high superheat temperatures controllable over awide range, even to zero superheat, has substantially increased theprobe lems of design and construction. One-such unit involves the use ofa separately fired auxiliary furnace chamber in the same setting forregulably heating the steam superheating surface. To reduce the spacerequirements of'the unit and ship adaptation to it and to morecffectively utilize the heating gasesfro'r'r'i the aux-,

furnace through the main furnace chamber tends to interfere with thecombustion infthe'main' furnace chamber due to the consequentintroduction of a substantial amount of relatively cold inert gasestherein.

, The main object of my invention is the provision of an improvedconstruction of a steam generating unitof the general type describedwhich is particularly characterized by its compactness, effectivesuperheat control over awide range, advantageous" -combustion conditions-in' are connected to external inclined headers?! both the main andauxiliary furnaces, and highoverall efficiency. g

The various features'of novelty which characterize my invention arepointed out with par-.

ticularity in the claims annexed to and forming a part of thisspecification. For a better under standing of the invention, itsoperating advantages and specific objects attained'by' its use,

reference should be had to; the accompanying drawing and descriptivematter-in which I have illustrated and described a preferred b g ment ofmy invention. 1 4 v I Of the drawing:

Fig. 1 is a partly diagrammatic sectional elevation of a steamgeneratijngunit' constructed in accordance with-my invention; and

Fig. 2 is a section'taken on the linZ-Z of Fig. 1. I. g r

The steam generating unit illustrated "co prisesa setting ill enclosinga relatively wide bank of inclined steam generatingtubes Il ex. tendingbetween a lower'waterdrum i2and an upper steamjand water drum l3laterally offset from and of substantially larger diameter than the drum[2. At the opposite'side of the setting is arranged a bank of inclinedsteam generating tubes l lextending between thedrum i3 and a lower Waterdrum [5. The tube "banlgs'yil and M define, therebetween an A-shapedspace closed at its endsby the vertical end walls'of'the setting, andextending downwardly to a refractory bottom pan [6 below the levelof thedrums l2 and 15. The setting is provided'with a single heating'gasoutlet flue I l at the outer side of the tube bank 'I l, i. e. the sideopposite the 'A-shaped space, and adjacent to the steam and water drum53. A bank'of economizei' or air heater i8 is positioned in'the outletflue ll.

Inaccordance with my invention the tube bank 54 is divided intothree'spaced groups of water tubes I4 M and M The group l t containsonly a relatively few rows of tubes at the inner side of the bankandserves as a waterscreenfor a superheater hereinafter described. Thetubes M are of larger diameter than thetube's' It? or Mand'are,arrangedin a single row intermediateithose groups. "The tubes ll also serve as. supports for an' inclined bank of U- shaped steamsuperheating tubes 29 extending transversely of theltube bank I4 in thelowerportion of the space between the tube groups M and M The ends ofthew-shaped superheater'tubes and'22; with the header 2! arrangedfto'receive saturated steam from the steam and water drum i3 throughpipes-23. The tubesf i lare" of some,-

what l'."-sh'ape,- and arranged toextend along and support thecorrespondingside'w'all 'of'th'e setting Hl. The tube group M also hasonly a few rows and is arranged withthe longer legs of the tubessubstantially spaced from the superheatentubes 20. I

' The A-shaped space between thatube banks H and I4 serves' as'thecombu's'tionspaceofthe unit,"and isfplefiablY divided i lito a ln lilrfur nace chamber 25 and an auxiliary furnace chamber 26 by a row oftubes 21 extending from a header 28 to the drum l3. The header 28 isarranged along the bottom l6 below the steam and water drum l3 andconnected by supply tubes 29 to the drum IS. The tubes 21 are bentlaterally at an intermediate point towards the tubes l4 and extendupwardly along the inner side of the same from a point adjacent theupper end of superheater tubes 20. The tubes 21 are fully studded, asshown in Fig. 2, for a portion of their length and the studs covered andintertube spaces 7 header 28 to the tube bank It at a point adjacent Ithe upper end of the superheater. A metallic baffle 32 extends laterallyfrom the upper end of the partition across the tubes M and N along theupper end of the superheater tube group, ter minating at the outer sideof the superheater. The main furnace chamber is fired by a group offluid fuel burners 35 arranged to discharge longitudinally thereofthrough corresponding burner ports 36 located in one of the end walls ofthe setting. The auxiliary furnace chamber 26 is fired by similarlyarrangedindependently operable fluid fuel burners 31 through burnerports 38. The burners 31 can be operated as desired to control thesuperheat temperatures over a relatively wide range, eitherautomatically or manually, suitable automatic mechanism for this purposebeing well known. As an alternative the boiler can be operated toproduce saturated steam and without superheating it by using the maifurnace chamber 25, and not using the auxiliary furnace chamber 26.

With the described construction the steam generating unit is started upwith only main furnace chamber burners 35 in use. The heating gasesgenerated by the fuel burning in suspension flow transversely of thetube bank I I to the gas outlet flue ll, passing over the economize;tubes is before leaving the unit. During the starting-up period thefluid-cooled partition 3! forms an effective radiant heat shield betweenthe main furnace chamber and the auxiliary furnace chamber and itsassociated parts, particularly the superheater tubes 29. Withsteamflowing through the superheater tubes, the auxiliary furnacechamber burners 31 are put into operation. The heating gases generatedin the auxiliary furnace chamber flow upwardly across the screen tubesi4 and superheater tubes 29, the flow path in this section being definedby the setting walls, the partition 3!, and bafile 32,, Aiter leavingthe superheater tubes 20 the gases flow around the upper end of thebaffle 32 while contacting with the tubes H. The space between thesuperheater tubes and tubes [4 serves as a gas flow equalization andturning space, permitting a reversal in direction of the gas flow with arelatively low pressure drop. The gases on rounding the bafiie 32 flowacross the upper portions of the tubes M I la, and 2'1. The heatinggases from the auxiliary furnace chamber then flow across the upperportion of the main furnace h m nd upper part of the tube bank, Ii tothe gas outletfiue i1.

The described flow path of the auxiliary furnace gases insures anefficient use of the heat values thereof, and a minimum interferencethereby with the combustion conditions-in the main furnace chamber. Thedescribed steam generating unit with its integrally arranged inndsingle,

gas outlet provides an extremely compact structure having relatively lowfloor space and head room requirements. The construction and arrangementof the main and auxiliary furnace chambers permits the maintenancetherein of combustion conditions contributing to a high thermaleificiency of the unit. The arrangement of the auxiliary furnace chamberand its associated parts insures effective control of superheatconditions over a wide range and with a I high upper limit.

While in accordance with the provisions of the statutes I haveillustrated and described herein the best form of the invention nowknown to me, those skilled in the art will understand that changes maybe made in the form of the apparatus disclosed without departing fromthe spirit of the invention covered by my claims, and that certainfeatures of my invention may sometimes be used to advantage without acorresponding use of other features.

I claim:

1. A steam generator comprising a setting, an upper steam and waterdrum, a pair of spaced lower water drums, a bank of inclined steamgenerating tubes connecting said upper drum to one of said lower drums,a group of steam generating screen tubes connecting the upper drum tothe other of said water drums, a vertically arranged partition arrangedto divide the space between said tube bank and said screen tube groupinto a main furnace chamber and a laterally adjoining auxiliary furnacechamber, the portion of said group of screen tubes extending throughoutone side of said auxiliary furnace chamber being unobstructed, means forfiring said main furnace chamber, a group of superheater tubes extendingalong the outer side of said unobstructed portion of said screen tubegroup and of said auxiliary furnace chamber, means for independentlyfiring said auxiliary furnace chamber, a single heating gas outlet flueat the outer side of said tube bank and arranged to receive all of theheating gases flowing from both of said furnace chambers, said fluebeing so located that the heating gases from said auxiliary furnacechamber flow over said unobstructed screen tube group portion,superheater tubes. and tube bank and across said main furnace chamberbefore entering said flue, and said partition terminating below saidupper drum and arranged to direct the heating gas flow from saidauxiliary furnace chamber over said superheater tubes and into the upperpart of said main furnace chamber and to shield said super-heater tubesfrom flame radiation from said main furnace chamber.

2. A steam generator comprising a setting, an upper steam and waterdrum, a pair of spaced lower water drums at substantially the samelevel, a bank of inclined steam generating tubes connecting said upperdrum to one of said lower drums, a group of inclined steam generatingscreen tubes connecting the upper drum to the other of said water drums,a vertically arranged fluid cooled partition arranged to divide thespace between said tube bank and said screen tube group into a mainfurnace chamber and a laterally adjoining auxiliary furnace chamber, theportion of said group of screen tubes ex tending throughout one side ofsaid auxiliary furnace chamber being unobstructed, means for firing saidmain furnace chamber, a group of horizontally arranged superheater tubesextendn e .n .i1w Pa e s P s n b t cted.

portion of said screen tube group and of sald auxiliary furnace chamber,means for independently firing said auxiliary furnace chamber, a

single heating gas outlet fiueat the outer side of said tube bank andarranged to receive all a of the'heating gases flowing from both offsaidfurnace chambers; said flue being so located that the heating gases fromsaid auxiliary furnace chamber flow over said unobstructed screen tubegroup portion, superheater tubes-and tube bank 1 2,332,508 a 3 andacross said main furnace chamber beforeentering said flue, and saidfluid-cooled partition terminating below said upper drum and arranged todirect the heating gas flow from said auxiliary furnace chamber oversaid superheater tubes and into the upper part of said main furnacecham-s I her and to shield said superheater' tubes from flame radiationfrom said main furnace chamber. s

GEORGE H. DANIELS.

